全文获取类型
收费全文 | 1883篇 |
免费 | 40篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 140篇 |
综合类 | 2篇 |
化学工业 | 278篇 |
金属工艺 | 41篇 |
机械仪表 | 34篇 |
建筑科学 | 35篇 |
矿业工程 | 1篇 |
能源动力 | 34篇 |
轻工业 | 155篇 |
水利工程 | 9篇 |
无线电 | 240篇 |
一般工业技术 | 240篇 |
冶金工业 | 546篇 |
原子能技术 | 37篇 |
自动化技术 | 137篇 |
出版年
2022年 | 22篇 |
2021年 | 38篇 |
2020年 | 17篇 |
2019年 | 12篇 |
2018年 | 30篇 |
2017年 | 16篇 |
2016年 | 20篇 |
2015年 | 19篇 |
2014年 | 38篇 |
2013年 | 56篇 |
2012年 | 38篇 |
2011年 | 69篇 |
2010年 | 49篇 |
2009年 | 63篇 |
2008年 | 65篇 |
2007年 | 53篇 |
2006年 | 49篇 |
2005年 | 60篇 |
2004年 | 46篇 |
2003年 | 34篇 |
2002年 | 54篇 |
2001年 | 29篇 |
2000年 | 44篇 |
1999年 | 50篇 |
1998年 | 203篇 |
1997年 | 125篇 |
1996年 | 93篇 |
1995年 | 67篇 |
1994年 | 58篇 |
1993年 | 65篇 |
1992年 | 36篇 |
1991年 | 26篇 |
1990年 | 18篇 |
1989年 | 24篇 |
1988年 | 28篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 21篇 |
1984年 | 20篇 |
1983年 | 15篇 |
1982年 | 18篇 |
1981年 | 16篇 |
1980年 | 12篇 |
1979年 | 14篇 |
1978年 | 7篇 |
1977年 | 18篇 |
1976年 | 16篇 |
1975年 | 7篇 |
1974年 | 6篇 |
1967年 | 6篇 |
排序方式: 共有1929条查询结果,搜索用时 0 毫秒
41.
42.
Yuta Fujita Akihiro Ametani Keisuke Nakamura Koichi Yamabuki 《Electrical Engineering in Japan》2014,188(1):36-45
This paper investigates the mutual grounding impedance between vertical grounding electrodes based on field measurements and FDTD simulations. In the case of vertical electrodes, the mutual impedance between the electrodes is almost completely independent of the electrode length, and thus the induced voltage is nearly constant as the electrode length becomes longer. This characteristic is different from that of an overhead conductor, where the electromagnetic‐induced voltage is proportional to the conductor length. The greater the separation distance between the electrodes, the smaller the induced voltage, as in the case of an overhead conductor. The propagation speed increases as the separation increases. It is found that the speed is not necessarily proportional to the inverse of the relative permittivity of the earth. 相似文献
43.
Yttrium aluminum garnet (YAG) doped with Ce3+ ion is known as an excellent phosphor for light-emitting diode (LED), usually used as a powder form dispersed in organic resins. We have developed translucent glass-ceramics (GC) of YAG: Ce3+ microcrystals in 2004. The GC sheet with half millimeter thick can work efficiently to make identical emission spectra with conventional white LED when combined with a blue LED. This report reviews the development history of the GC materials and impact for all inorganic solution for solid-state lighting. 相似文献
44.
Nao. Fujita Y. Zushi Y. Saito 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(6):921-924
Fe-54at.%Rh thin films were irradiated with 10 MeV iodine ions at room temperature. Before and after the irradiations, the changes in magnetic properties and the lattice structure of the samples were studied by means of a SQUID magnetometer and X-ray diffraction. For the low fluence irradiation, the SQUID measurement at 20 K shows that the anti-ferromagnetic region of the thin film is changed into ferromagnetic region by the irradiation. As the film thickness is much smaller than the ion range, we can discuss the relationship between the density of energy deposited by ions and the change in magnetization quantitatively. For the high fluence irradiation, the magnetization of the film is strongly decreased by the irradiation, which can be explained as due to the change in lattice structure from B2 into A1 structure by the irradiation. 相似文献
45.
Yasushi Fujita Denan Jin Masashi Mimura Yohei Sato Shinji Takai Teruyo Kida 《International journal of molecular sciences》2022,23(5)
The purpose of this present study was to investigate the distribution and expression of chymase in the lacrimal glands (LGs) of patients afflicted with IgG4-related ophthalmic disease (IgG4-ROD). LGs from patients with severe canalicular obstruction were considered the control group. Toluidine blue staining confirmed a significant increase in the number of mast cells in the LGs obtained from the IgG4-ROD patients. In addition, immunostaining of serial sections from the LGs showed a significant increase in the number of chymase-positive cells and tryptase-positive cells in the IgG4-ROD LGs compared to the normal control LGs. The mRNA expression of chymase, tryptase, TGF-β1, and collagen-I tended to increase in the IgG4-ROD LGs. Immunostaining of vimentin and α-smooth muscle actin (α-SMA) showed that myofibroblasts were the main cellular components in severely fibrotic regions of LGs in patients with IgG4-ROD. Linear regression analyses on the number of mast cells, chymase-positive cells, and tryptase-positive cells revealed significant positive correlations between those respective cells. Our findings suggest that chymase may play a role in the fibrotic disorder of IgG4-ROD LGs through the regulation of TGF-β1 activation and collagen-I deposition, and that it may be a therapeutic target for patients afflicted with IgG4-ROD. 相似文献
46.
47.
48.
49.
50.
T Takeshita T Arita H Asao N Tanaka M Higuchi H Kuroda K Kaneko H Munakata Y Endo T Fujita K Sugamura 《Canadian Metallurgical Quarterly》1996,225(3):1035-1039
We molecularly cloned a cDNA coding for a novel phosphotyrosine molecule with a 70 kDa molecular mass, named STAM (signal transducing adaptor molecule), which is tyrosine-phosphorylated rapidly after stimulation with various cytokines such as IL-2, IL-3, IL-4, IL-7, GM-CSF, EGF and PDGF. STAM contains an SH3 (Src-homology 3) domain and the ITAM (immunoreceptor tyrosine-based activation motif), suggesting that STAM acts as an adaptor molecule involved in signal transducing pathways from the cytokine receptors. 相似文献